鼎湖山季风常绿阔叶林林下层3种优势树种游离氨基酸和蛋白质对模拟氮沉降的响应  

Effects of simulated N deposition on free amino acids and soluble protein of three dominant understory species in a monsoon evergreen broad-leaved forest of subtropical China

作　　者：鲁显楷[1] 莫江明[1] 彭少麟[2] 方运霆[1] 李德军[1] 林琼芳[3] 

机构地区：[1]中国科学院华南植物园鼎湖山森林生态系统定位研究站 [2]中山大学生命科学学院,广州510275 [3]广东省昆虫研究所,广州510260

出　　处：《生态学报》2006年第3期743-753,共11页Acta Ecologica Sinica

基　　金：中国科学院知识创新工程重大资助项目(KSCX2-SW-133);国家自然科学基金资助项目(30270283);中国科学院知识创新领域前沿资助项目;中国科学院华南植物研究所所长基金资助项目~~

摘　　要：报道了林下层3种优势树种光叶山黄皮(Randia canthioides)、黄果厚壳桂(Cryptocarya concinna)和厚壳桂(Cryptocaryachinensis)叶片游离氨基酸和蛋白质对模拟氮沉降的响应,并探讨这3种植物中重要氨基酸对氮沉降的指示作用,以及γ-氨基丁酸含量的变化对植食性动物的可能影响,为揭示氮沉降对森林植物生理生态影响及其机理,以及监测氮沉降对植被的影响等一系列问题提供初步的理论基础。结果表明,试验21个月后,3个树种叶片游离氨基酸和蛋白质的含量均发生了明显的变化。对总的游离氨基酸含量而言,光叶山黄皮和厚壳桂对氮处理的响应相似,氮处理样地的含量均高于对照,并且中氮处理显著高于对照(p<0.05),但两者在高氮处理下均出现了下降的趋势;黄果厚壳桂随着氮处理强度的增加,游离氨基酸总量呈现下降趋势。对于可溶性蛋白质含量来说,光叶山黄皮、黄果厚壳桂和厚壳桂在氮处理下都出现了增加的趋势,黄果厚壳桂和厚壳桂增加尤为明显。找出了对氮沉降响应敏感的指示剂。游离氨基酸丝氨酸、精氨酸和γ-氨基丁酸,特别是精氨酸,可以用来作为光叶山黄皮对氮沉降响应的指示剂;γ-氨基丁酸可以作为黄果厚壳桂对氮沉降响应的指示剂;丝氨酸和γ-氨基丁酸可以作为厚壳桂对氮沉降响应的指示剂。个别游离氨基酸的积累情况可被用来监测氮沉降对植被的影响。Elevated nitrogen （N） deposition has been show to have a variety of effects on to forest ecosystems, including nutrient imbalance, growth disturbance, and foliar accumulation of free amino acids in individual plants. The purpose of this study is to determine the effects of simulated N deposition on free amino acids and soluble protein of three dominant understory plants （ Randia canthioides, Cryptocarya concinna, and Cryptocarya chinensis） in a monsoon evergreen broad-leaved forest of subtropical China. The experimental design was a randomized complete block with three replications （sets of plots） and four N treatments. The treatments consisted of Control （0 kg hm^-2 a^-1）, Low N （50 kg hm^-2 a^-1）, Medium N （100 kg hm^-2 a^-1） and High N （ 150 kg hm^-2 a^-1 ）. Each plot covered an area of 1020 m^2 surrounded by a lO-m-wide buffer zone. From July 2003, NH4NO3 solution, with concentrations of about 0, 0.3, 0.6 and 0.9 mol N·L^-1 respectively for Control, Low N, Medium N and High N treatments, was sprayed onto the forest floor of these plots once every month. Here, we reported the results after 21 months of treatment. Results indicated that nitrogen addition at all levels affected the free amino acid concentrations and soluble protein concentrations of the three tree species. The composition of the free amino acid pool and the dominant amino acids varied with species. The dominant amino acids by species were. aspartic acid, serine, glutamic acid, arginine and γ-aminobutyric acid （ γ- GABA） for Randia canthioides; aspartic acid, serine and γ-aminobutyric acid for Cryptocarya concinna; and aspartic acid, serine, glutamic acid and γ-aminobutyric acid for Cryptocarya chinensis. For Randia canthioides and Cryptocarya chinensis, the responses of the total free amino acid concentrations to simulated N deposition were similar, with the concentrations in trees of N- treated plots higher than those of the Control. For Cryptocarya concinna, the total free amino acid concentrations sh

关 键 词：氮沉降 游离氨基酸 蛋白质 γ-氨基丁酸 季风常绿阔叶林 指示剂 南亚热带 

分 类 号：S718.5[农业科学—林学]